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Fix Your Stuff

Right to Repair



Original post by: Dan ,


The signal logic which pumps the video signal to either of the two Thunderbolt ports as well as the HDMI port, the MUX logic is quite complex. You’ll need to find someone with the deeper skills to fix your logic board or you can replace it.

I don’t think your OS upgrade did you in. To be doubly sure you could create a fresh bootable drive using an external Thunderbolt or USB drive, formatting it and installing macOS Catalina. Then booting up under it using the Option key to get to the startup manager.

Reference: [|Mac startup key combinations]